1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a curved display screen.
2. Background Art
Thanks to several characteristics of a liquid crystal display device such as the reduction of thickness of the display device and the reduction of weight of the display device, a demand for a liquid crystal display device has been spreading to various applications ranging from a computer display, a mobile phone terminal or the like to a television receiver set. It is also one of the characteristics of the liquid crystal display device that the liquid crystal display device has a planar screen.
From a viewpoint that a liquid crystal display device can be made thinner, the liquid crystal display device has a possibility of being installed at various places. The installation place of the liquid crystal display device is not limited to a planar plane and there has been also a demand for installation of the liquid crystal display device on a place which has a curved plane. As such an installation place which has a curved plane, for example, a pillar having a circular cross section, a wall surface of a train or a bus or the like is named. Further, there also exists a case in which it is necessary to form a display device per se in a curved plane. For example, a pachinko machine, a slot machine gaming machine, and various gaming machines installed in a gaming arena are named. In an attempt to use a liquid crystal display device as a display of such a gaming machine, it is necessary to form the liquid crystal display device in a curved plane.
However, the manufacture of the liquid crystal display panel using a curved glass substrate or the like is extremely difficult. Accordingly, a flat liquid crystal display panel is firstly manufactured using a flat glass substrate and, thereafter, the liquid crystal display panel is curved. Here, an operation for uniformly forming the flat liquid crystal display panel in a curved plane requires a special technique.
JP-A-8-286174 (Patent document 1) discloses a technique which forms the liquid crystal display panel in a curved plane using a particular polarizer to be adhered to a flat liquid crystal display panel formed using a glass substrate. That is, by adhering the polarizer which is curved along an absorption axis of the polarizer when the polarizer is heated or moistened, the liquid crystal display panel is curved.
JP-2006-106079 (Patent document 2) discloses a technique which, in curving the flat liquid crystal display panel, a uniaxial stretching film is adhered to a recessed surface side of the liquid crystal display panel and leaves the liquid crystal display panel in an atmosphere of a temperature of 40° C. to 200° C. for 10 minutes to 24 hours so as to curve the flat liquid crystal display panel. That is, the liquid crystal display panel is curved by making use of shrinkage of the uniaxial stretching film in the stretching direction.